Asterisk on Android creating SIP-GSM gateway

I need an application that runs on Android phones (4.0 or above) and can send/receive calls through SIP (Can use any sip stack like sipdroid) and forward it to the GSM network. The application should then forward the audio and convert from SIP to GSM and vice versa. Full description below. Please review and message me with considerations. If any requirements are unable to be met, please let me know before we make a deal. Summary The goal of this project is to develop an Android application that can send calls through SIP and forward them to the GSM network AND receive calls from GSM and forward to SIP. The application should then forward the audio and convert from VoIP to GSM and vice vers General Deliveries The application working in APK format Full source code Simple manual for compiling and generating the application from source A SIP client running on another phone that connects to the server via WIFI and able to demonstrate the functionality in this project. Features - Route call from SIP to GSM - Route call from GSM to SIP (preconfigured SIP client) - Convert audio from/to SIP and GSM networks - Able to run on Android 4.0 and up. Application Configurations - Enable or disable the app - Enable to receive calls only on wifi or all networks - Enable to route calls from GSM to SIP (SIP address is configured through an API) - The number to send the call should be configured through an API that is supplied with the APP - Enable to route calls from SIP to GSM - Must run on background - Must be very lightweight to run on small memory devices - Configure SIP Accounts.